John Gwyn Jeffreys: Wales’s Pioneer of Deep-sea Exploration

John Gwyn Jeffreys was a famous Swansea-born Welsh naturalist and a pioneer of deep-sea exploration in the 1800s.
At Amgueddfa Cymru we hold shells he collected in deep-sea expeditions, his stunning shell cabinet on display at St Fagans Castle and letter archives from 1840–54. We even have the blotting paper he used when writing his letters!
Find out about his life, his influences and the discoveries he made about molluscs and the deep sea.

John Gwyn Jeffreys (1809–1885) was one of Britain's most eminent 19th-century conchologists (mollusc shell experts) with a passion for dredging and deep-sea exploration. From his early beginnings exploring Swansea Bay in a rowing boat, he went on to lead deep-sea expeditions in British and European seas, finding life at previously unknown depths. We owe much of our knowledge of deep-sea life to the pioneering work undertaken by Jeffreys and his fellow explorers of the time.

“There is a magnet-like attraction in
These waters to the imaginative power
That links the viewless with the visible,
And pictures things unseen”

(Poem quoted in a Jeffreys lecture, 1881)

Who was John Gwyn Jeffreys?

Early years of inspiration

John Gwyn Jeffreys was born in Abertawe on 18 January 1809 and was a descendent of one of the oldest families in Wales. From a young age, he was interested in natural history, and it was at Swansea Grammar School that he had his first lesson in shell collecting, putting him on a path that he would not deviate from for the rest of his life.

At the age of 17, Jeffreys was apprenticed to a Swansea solicitor, but he continued to develop his passion for shells and collecting by being active in the local natural history community. Here he met Lewis Weston Dillwyn (1778–1855), well known for Swansea pottery production but also a keen natural historian. It was under his influence that Jeffreys was encouraged to produce his first scientific paper, when he was 19 years old.

Jeffreys was successful as a solicitor in Swansea for many years and this allowed him to indulge in natural history during his spare time. He devoted his holidays to finding new species and varieties of molluscs, initially dredging from a rowing boat and later from his yacht, the Osprey. His desire for unusual and new species took him north, especially to Shetland where he could dredge the deeper waters close to shore. This hands-on approach gave him a valuable insight into more than just shells, but also how they lived, the habitats they survived in and how different species lived together and interacted.

Retiring to research

In 1856, Jeffreys and his family left Swansea so that he could become a barrister in London, where they remained for 10 years. At 57, Jeffreys made the decision to retire from Law and moved to Hertfordshire, so that he could finally fully dedicate himself to his primary passion of natural history.

Letters from afar

Jeffreys communicated with almost every European conchologist of his time, and kept a meticulous record of each letter that he sent out. In 2009, Amgueddfa Cymru acquired two volumes of his early letters, written between 1840 and 1854 when he was living in Swansea.

The letter-books reveal the intricate business of conchology at work, including plans for future voyages and scientific discussions. This is well illustrated by the 51 letters to Edward Forbes, a fellow passionate dredger and one of the founders of British marine biology. Although great friends, they were also potential competitors, both aspiring to publish the definitive book on British molluscs.

Many of the famous naturalists of the day are included in these books; there is even a letter written to Charles Darwin! However, Jeffreys was never able to accept the theory of evolution, believing that species do not change over time.

Jeffreys shared his knowledge!

“The dredge surpasses all other methods of investigating the fauna of the ocean”

(John Gwyn Jeffreys, 1862)

During his life, Jeffreys published around 200 scientific papers, but his most significant publication was British Conchology. This series was issued in five volumes between 1862 and 1869, featuring 132 plates of beautiful shell illustrations.

It is an important work, as it gives descriptions of each species with accounts of their biology and where they are found, both in British waters and elsewhere. It is still a standard reference today.

Jeffreys used this series to try to popularise the study of shells; he made the pages pleasant reading and non-technical where possible. However, this did cause the series to be longer than necessary, more costly and therefore, too expensive for many working conchologists.

Within everything Jeffreys wrote on shells, he described 41 new genera (named groups of closely-related species, such as Homo, our own genus) and 585 new species.

Examples of plates of illustrations from British Conchology

Jeffreys’s shell collection

“I know the collection to be unrivalled and as perfect as probably any … can be; and I have not spared pains or money to complete it … The arrangement of the collection would occupy you probably two or three years and when arranged it would be ‘a sight fit for a King’”

(Jeffreys to William Clark, 4 February 1849)

An unrivalled collection

Jeffreys amassed a large and comprehensive shell collection. It was described as unrivalled for British marine molluscs at the time of his death. The collection contained examples of over 700 mollusc species, averaging 50 specimens per species!

It held examples of every new species described by Jeffreys in his work British Conchology and in his subsequent papers. It also contained the original collections of other early British naturalists such as William Turton, Joshua Alder and William Clark, whose collections he had acquired.

The sale of the collection

At the age of 40 years old, Jeffreys considered selling his collection. At this time, he estimated its worth at £1000, the equivalent of around £150,000 in today’s money!

In his later years, Jeffreys offered his collection to the Natural History Museum, London, but the offer was not accepted – due to a lack of space, not because they didn’t want it.

The collection was eventually sold to the American collector William Dall for £1050, who then sold it on to the Smithsonian Institution. This sale was described as “a grievous loss, not only to Britain but to European conchologists” and as “a national tragedy”.

The Jeffreys collection is still at the Smithsonian Institution, USA, although some shells from most of the expeditions he worked on are held at the Natural History Museum, London.

At Amgueddfa Cymru, there is a small collection of Jeffreys’s Welsh freshwater molluscs, which were donated to us by the Smithsonian Institution in 1970 and 1971. The Melvill-Tomlin collection also contains specimens collected by Jeffreys from several of his deep-sea expeditions.

Jeffreys’s shell cabinet

The cabinet

Whilst living in Swansea, Jeffreys commissioned a cabinet to be made to hold his extensive shell collection. This cabinet was acquired by Amgueddfa Cymru in 2004 and it now has pride of place in the library of St Fagans Castle.

The main body of the cabinet has double doors, which open to display two columns of glass-topped mahogany collection drawers.

The entire cabinet is expertly hand-made from Cuban and Honduran mahogany, including the use of book-matched pieces for the veneer that give a symmetrical, fiddle-back appearance.

On the cabinet top is an ornate wood carving, heavily pigmented to form a dramatic silhouette. A scallop shell forms a fan at the centre and the shell of a female paper nautilus sits at either end, giving just a hint to what might once have been inside.

Carvings on the top of Jeffreys’s cabinet

Where and when was the cabinet made?

The provenance of the cabinet is unclear. It was sold at Sotheby’s in 2001 and Christie’s in 2004, as a Victorian Gillows piece. This would place its production in London. However, our Amgueddfa Cymru furniture conservator has identified it as a possible William the Fourth or early Victorian cabinet, dating from the second quarter of the 19th century, and suggests it may be an important piece of Welsh furniture.

There is evidence that both Jeffreys’s cabinet and collection had a 5 year stay at the Museum of the Royal Institution of South Wales (now the Swansea Museum). Jeffreys wrote to Dr Nicol, the Honorary Secretary, in 1854 explaining that it would reside there “…until I return to this neighbourhood or have other reasons for desiring its removal” and he went on to say, “When I return I hope to have leisure to complete the arrangement, and then the collection will at all times be accessible to the members of the Institution.”

A train label on the underside of the cabinet tells us more about its history and reveals that it travelled from Swansea to Jeffreys’s London residence in 1859, where Jeffreys was working as a barrister.

Is there life at the bottom of the ocean?

“I detest the sea for its own sake, but put up with the discomforts for the sake of science or natural history”

(John Gwyn Jeffreys)

The belief that sea life did not exist below 550m was known as the ‘Azoic theory’ and was proposed in the 1840s by Jeffreys’s friend Edward Forbes. The theory was commonly believed for nearly three decades.

In the 1860s, the feasibility of exploring much greater depths using deep-sea dredging evolved and the British pioneers W. B. Carpenter and C. Wyville Thomson requested support from the Royal Society and the Admiralty “with a view to ascertain the existence and zoological relations of animals at great depths”.

In 1868, they were granted use of the HMS Lightning for an experimental cruise and, although blighted by bad weather and cut short, a successful haul was brought up from 1189m.

A year later, they extended their research on the first HMS Porcupine expedition. Jeffreys was the scientific leader for the first leg of this historic voyage, which included dredging to 4289m in waters south-west of Ireland. This was by far the deepest dredge haul ever attempted and, by bringing up a mass of mud containing many kinds of animals, they blew Forbes’s Azoic theory out of the water!

Jeffreys continued to take part in many deep-sea expeditions, notably Porcupine II (Atlantic and Mediterranean, 1870), Valorous (Greenland, 1875) and the French Travailleur expedition (Bay of Biscay, 1880). He also identified, and wrote scientific reports on the molluscs from the following expeditions:

Josephine expedition, 1869

A Swedish expedition, mainly dredging among the Azores and in the West-Indies.

Shearwater expedition, 1871

Carpenter led this expedition from England to the Red Sea, via the Mediterranean. He was particularly interested in continuing his research into deep-water oceanic currents between the Atlantic and Mediterranean, which he had started on the Porcupine II expedition.

Travailleur and Talisman expeditions, 1880–1882

In 1880, by invitation of the French government, Jeffreys and his colleague, Dr Norman, went together to dredge in deep waters off the Bay of Biscay. This was part of a series of French expeditions working in the area from the Bay of Biscay to the Sargasso Sea, and south to Senegal.

Washington expedition, 1881

An Italian expedition in the Mediterranean, operating off the west coasts of Italy and Sicily, in depths from 60m to 3630m.

Triton expedition, 1882

This expedition was commissioned to investigate the Wyville-Thomson Ridge, in the Faroe-Shetland Channel.

This article has been brought together using material from the Hurrah for the Dredge! exhibition curated by Harriet Wood, Jennifer Gallichan and Anna Holmes in 2009.

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